Implementation of a Realistic Multicell CFD Model to Investigate the Thermal Characteristics Within a Solar PV Module

Abstract

The thermal characteristics within a solar photovoltaic (PV) module are vital in determining its real field power output and lifetime. The structural and thermal complexities within a PV module have often been ignored in the past CFD-based research works. However, those complexities can substantially impact the thermal diffusion occurring within the module. The present study proposes a realistic multilayered multicell model in which the PV cells are considered as multiple distinct domains with encapsulant-filled discontinuities. The model is validated with experimental results and then implemented to investigate the cell temperature, thermal profile, and temperature gradients within a free-standing PV module in various wind conditions. The low thermal conductance of discontinuities among PV cells is found to be the key factor in raising the cell temperature 2°C–3°C above the back temperature. The current mismatch loss due to temperature nonuniformity is estimated to be up to 0.28% for a 50 W module and should be higher in bigger-size modules. Very high-temperature gradients (order of 10³°C/m) are observed in the encapsulant and backsheet layers near the cell edges, which can lead to high thermal stress and consequent degradation. The back temperature, temperature pattern along the surface, and location of hotter zones remain largely unaffected by the discontinuities among PV cells.